arXiv - PHYS - Instrumentation and Methods for Astrophysics最新文献

{"title":"Lunar References Systems, Frames and Time-scales in the context of the ESA Programme Moonlight","authors":"Agnes Fienga, Nicolas Rambaux, Krzysztof Sosnica","doi":"arxiv-2409.10043","DOIUrl":"https://doi.org/arxiv-2409.10043","url":null,"abstract":"Lunar reference systems represent a fundamental aspect of lunar exploration.\u0000This paper presents a review of the topic in the context of the ESA lunar\u0000programme, MoonLight. This paper describes the current state of the art in the\u0000definition of the lunar reference frame and introduces TCL, a lunar time scale\u0000based on IAU resolutions. It also proposes several possible implementations of\u0000this time scale for orbiting and ground-based clocks. Finally, it provides an\u0000assessment of the improvement of the lunar reference frame that would result\u0000from the addition of lunar retro-reflectors on the Moon surface and the use of\u0000orbiter altimetry. This document is an appendix dedicated to lunar reference\u0000system definition of a more global document dedicated to the presentation of\u0000new concepts in orbit determination and time synchronization of a lunar radio\u0000navigation system.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sherpa: An Open Source Python Fitting Package","authors":"Aneta Siemiginowska, Douglas Burke, Hans Moritz Günther, Nicholas P. Lee, Warren McLaughlin, David A. Principe, Harlan Cheer, Antonella Fruscione, Omar Laurino, Jonathan McDowell, Marie Terrell","doi":"arxiv-2409.10400","DOIUrl":"https://doi.org/arxiv-2409.10400","url":null,"abstract":"We present an overview of Sherpa, an open source Python project, and discuss\u0000its development history, broad design concepts and capabilities. Sherpa\u0000contains powerful tools for combining parametric models into complex\u0000expressions that can be fit to data using a variety of statistics and\u0000optimization methods. It is easily extensible to include user-defined models,\u0000statistics, and optimization methods. It provides a high-level User Interface\u0000for interactive data-analysis, such as within a Jupyter notebook, and it can\u0000also be used as a library component, providing fitting and modeling\u0000capabilities to an application. We include a few examples of Sherpa\u0000applications to multiwavelength astronomical data. The code is available\u0000GitHub: https://github.com/sherpa/sherpa","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Focus diverse phase retrieval test results on broadband continuous wavefront sensing in space telescope applications","authors":"Hyukmo Kang, Kyle Van Gorkom, Meghdoot Biswas, Daewook Kim, Ewan S. Douglas","doi":"arxiv-2409.10500","DOIUrl":"https://doi.org/arxiv-2409.10500","url":null,"abstract":"Continuous wavefront sensing benefits space observatories in on-orbit optical\u0000performance maintenance. To measure the phase of a wavefront, phase retrieval\u0000is an attractive technique as it uses multiple point spread function (PSF)\u0000images that are acquired by the telescope itself without extra metrology\u0000systems nor complicated calibration. The focus diverse phase retrieval utilizes\u0000PSFs from predetermined defocused positions to enhance the dynamic range of the\u0000algorithm. We describe an updated visible light active optics testbed with the\u0000addition of a linear motorized focus stage. The performance of the phase\u0000retrieval algorithm in broadband is tested under various cases. While broadband\u0000pass filters have advantages in higher signal-to-noise ratio (SNR), the\u0000performance of phase retrieval can be restricted due to blurred image caused by\u0000diffraction and increased computing cost. We used multiple bandpass filters (10\u0000nm, 88 nm, and 150 nm) and investigated effects of bandwidth on the accuracy\u0000and required image acquisition conditions such as SNR, reaching accuracies\u0000below 20 nm RMS wavefront error at the widest bandwidth. We also investigated\u0000the dynamic range of the phase retrieval algorithm depending on the bandwidth\u0000and required amount of defocus to expand dynamic range. Finally, we simulated\u0000the continuous wavefront sensing and correction loop with a range of\u0000statistically generated representative telescope disturbance time series to\u0000test for edge cases.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The CRAFT Coherent (CRACO) upgrade I: System Description and Results of the 110-ms Radio Transient Pilot Survey","authors":"Z. Wang, K. W. Bannister, V. Gupta, X. Deng, M. Pilawa, J. Tuthill, J. D. Bunton, C. Flynn, M. Glowacki, A. Jaini, Y. W. J. Lee, E. Lenc, J. Lucero, A. Paek, R. Radhakrishnan, N. Thyagarajan, P. Uttarkar, Y. Wang, N. D. R. Bhat, C. W. James, V. A. Moss, Tara Murphy, J. E. Reynolds, R. M. Shannon, L. G. Spitler, A. Tzioumis, M. Caleb, A. T. Deller, A. C. Gordon, L. Marnoch, S. D. Ryder, S. Simha, C. S. Anderson, L. Ball, D. Brodrick, F. R. Cooray, N. Gupta, D. B. Hayman, A. Ng, S. E. Pearce, C. Phillips, M. A. Voronkov, T. Westmeier","doi":"arxiv-2409.10316","DOIUrl":"https://doi.org/arxiv-2409.10316","url":null,"abstract":"We present the first results from a new backend on the Australian Square\u0000Kilometre Array Pathfinder, the Commensal Realtime ASKAP Fast Transient\u0000COherent (CRACO) upgrade. CRACO records millisecond time resolution visibility\u0000data, and searches for dispersed fast transient signals including fast radio\u0000bursts (FRB), pulsars, and ultra-long period objects (ULPO). With the\u0000visibility data, CRACO can localise the transient events to arcsecond-level\u0000precision after the detection. Here, we describe the CRACO system and report\u0000the result from a sky survey carried out by CRACO at 110ms resolution during\u0000its commissioning phase. During the survey, CRACO detected two FRBs (including\u0000one discovered solely with CRACO, FRB 20231027A), reported more precise\u0000localisations for four pulsars, discovered two new RRATs, and detected one\u0000known ULPO, GPM J1839-10, through its sub-pulse structure. We present a\u0000sensitivity calibration of CRACO, finding that it achieves the expected\u0000sensitivity of 11.6 Jy ms to bursts of 110 ms duration or less. CRACO is\u0000currently running at a 13.8 ms time resolution and aims at a 1.7 ms time\u0000resolution before the end of 2024. The planned CRACO has an expected\u0000sensitivity of 1.5 Jy ms to bursts of 1.7 ms duration or less, and can detect\u000010x more FRBs than the current CRAFT incoherent sum system (i.e., 0.5-2\u0000localised FRBs per day), enabling us to better constrain the FRB emission\u0000mechanism model and use them as cosmological probes.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ANNZ+: an enhanced photometric redshift estimation algorithm with applications on the PAU Survey","authors":"Imdad Mahmud Pathi, John Y. H. Soo, Mao Jie Wee, Sazatul Nadhilah Zakaria, Nur Azwin Ismail, Carlton M. Baugh, Giorgio Manzoni, Enrique Gaztanaga, Francisco J. Castander, Martin Eriksen, Jorge Carretero, Enrique Fernandez, Juan Garcia-Bellido, Ramon Miquel, Cristobal Padilla, Pablo Renard, Eusebio Sanchez, Ignacio Sevilla-Noarbe, Pau Tallada-Crespí","doi":"arxiv-2409.09981","DOIUrl":"https://doi.org/arxiv-2409.09981","url":null,"abstract":"ANNZ is a fast and simple algorithm which utilises artificial neural networks\u0000(ANNs), it was known as one of the pioneers of machine learning approaches to\u0000photometric redshift estimation decades ago. We enhanced the algorithm by\u0000introducing new activation functions like tanh, softplus, SiLU, Mish and ReLU\u0000variants; its new performance is then vigorously tested on legacy samples like\u0000the Luminous Red Galaxy (LRG) and Stripe-82 samples from SDSS, as well as\u0000modern galaxy samples like the Physics of the Accelerating Universe Survey\u0000(PAUS). This work focuses on testing the robustness of activation functions\u0000with respect to the choice of ANN architectures, particularly on its depth and\u0000width, in the context of galaxy photometric redshift estimation. Our upgraded\u0000algorithm, which we named ANNZ+, shows that the tanh and Leaky ReLU activation\u0000functions provide more consistent and stable results across deeper and wider\u0000architectures with > 1 per cent improvement in root-mean-square error\u0000($sigma_{textrm{RMS}}$) and 68th percentile error ($sigma_{68}$) when tested\u0000on SDSS data sets. While assessing its capabilities in handling high\u0000dimensional inputs, we achieved an improvement of 11 per cent in\u0000$sigma_{textrm{RMS}}$ and 6 per cent in $sigma_{68}$ with the tanh\u0000activation function when tested on the 40-narrowband PAUS dataset; it even\u0000outperformed ANNZ2, its supposed successor, by 44 per cent in\u0000$sigma_{textrm{RMS}}$. This justifies the effort to upgrade the 20-year-old\u0000ANNZ, allowing it to remain viable and competitive within the photo-z community\u0000today. The updated algorithm ANNZ+ is publicly available at\u0000https://github.com/imdadmpt/ANNzPlus.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"210 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Classifications for Exoplanet and Exoplanetary Systems -- Could it be developed? I. Exoplanet classification","authors":"E. Plávalová, A. Rosaev","doi":"arxiv-2409.09666","DOIUrl":"https://doi.org/arxiv-2409.09666","url":null,"abstract":"When a star is described as a spectral class G2V, we know its approximate\u0000mass, temperature, age, and size. At more than 5,700 exoplanets discovered, it\u0000is a natural developmental step to establish a classification for them, such as\u0000for example, the Harvard classification for stars. This exoplanet\u0000classification has to be easily interpreted and present the most relevant\u0000information about them and divides them into groups based on certain\u0000characteristics. We propose an exoplanet classification, which using an easily\u0000readable code, may inform you about a exoplanet's main characteristics. The\u0000suggested classification code contains four parameters by which we can quickly\u0000determine the range of temperature, mass, density and their eccentricity. The\u0000first parameter concerns the mass of an exoplanet in the form of the units of\u0000the mass of other known planets, where e.g. M represents the mass of Mercury, E\u0000that of Earth, N Neptune, or J Jupiter. The second parameter is the mean Dyson\u0000temperature of the extoplanet's orbit, for which we established four main\u0000classes: F represents the Frozen class, W the Water class, G the Gaseous class,\u0000and R the Roaster class. The third parameter is eccentricity and the fourth\u0000parameter is surface attribute which is defined as the bulk density of the\u0000exoplanet, where g represents a gaseous planet, w - water planet, t -\u0000terrestrial planet, i - iron planet and s - super dense planet. The\u0000classification code for Venus, could be EG0t (E - mass in the range of the mass\u0000of the Earth, G - Gaseous class, temperature in the range from 450 to 1000 K, 0\u0000- circular or nearly circular orbit, t - terrestrial surface), for Earth it\u0000could be EW0t (W - Water class - a possible Habitable zone). This\u0000classification is very helpful in, for example, quickly delimiting if a planet\u0000can be found in the Habitable zone; if it is terrestrial or not.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Knobs and dials of retrieving JWST transmission spectra. I. The importance of p-T profile complexity","authors":"Simon Schleich, Sudeshna Boro Saikia, Quentin Changeat, Manuel Güdel, Aiko Voigt, Ingo Waldmann","doi":"arxiv-2409.09127","DOIUrl":"https://doi.org/arxiv-2409.09127","url":null,"abstract":"We investigate the impact of using multipoint p-T profiles of varying\u0000complexity on the retrieval of synthetically generated hot Jupiter transmission\u0000spectra modelled after state-of-the-art observations of the hot Jupiter\u0000WASP-39~b with JWST. We perform homogenised atmospheric retrievals with the\u0000TauREx retrieval framework on a sample of synthetically generated transmission\u0000spectra, accounting for varying cases of underlying p-T profiles, cloud-top\u0000pressures, and expected noise levels. These retrievals are performed using a\u0000fixed-pressure multipoint p-T prescription with increasing complexity, ranging\u0000from isothermal to an eleven-point profile. We evaluate the performance of the\u0000retrievals based on the Bayesian model evidence, and the accuracy of the\u0000retrievals compared to the known input parameters. We find that performing\u0000atmospheric retrievals using an isothermal prescription for the\u0000pressure-temperature profile consistently results in wrongly retrieved\u0000atmospheric parameters when compared to the known input parameters. For an\u0000underlying p-T profile with a fully positive lapse rate, we find that a\u0000two-point profile is sufficient to retrieve the known atmospheric parameters,\u0000while under the presence of an atmospheric temperature inversion, we find that\u0000a more complex profile is necessary. Our investigation shows that, for a data\u0000quality scenario mirroring state-of-the-art observations of a hot Jupiter with\u0000JWST, an isothermal p-T prescription is insufficient to correctly retrieve the\u0000known atmospheric parameters. We find a model complexity preference dependent\u0000on the underlying pressure-temperature structure, but argue that a p-T\u0000prescription on the complexity level of a four-point profile should be\u0000preferred. This represents the overlap between the lowest number of free\u0000parameters and highest model preference in the cases investigated in this work.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding posterior projection effects with normalizing flows","authors":"Marco Raveri, Cyrille Doux, Shivam Pandey","doi":"arxiv-2409.09101","DOIUrl":"https://doi.org/arxiv-2409.09101","url":null,"abstract":"Many modern applications of Bayesian inference, such as in cosmology, are\u0000based on complicated forward models with high-dimensional parameter spaces.\u0000This considerably limits the sampling of posterior distributions conditioned on\u0000observed data. In turn, this reduces the interpretability of posteriors to\u0000their one- and two-dimensional marginal distributions, when more information is\u0000available in the full dimensional distributions. We show how to learn smooth\u0000and differentiable representations of posterior distributions from their\u0000samples using normalizing flows, which we train with an added evidence error\u0000loss term, to improve accuracy in multiple ways. Motivated by problems from\u0000cosmology, we implement a robust method to obtain one and two-dimensional\u0000posterior profiles. These are obtained by optimizing, instead of integrating,\u0000over other parameters, and are thus less prone than marginals to so-called\u0000projection effects. We also demonstrate how this representation provides an\u0000accurate estimator of the Bayesian evidence, with log error at the 0.2 level,\u0000allowing accurate model comparison. We test our method on multi-modal mixtures\u0000of Gaussians up to dimension 32 before applying it to simulated cosmology\u0000examples. Our code is publicly available at\u0000https://github.com/mraveri/tensiometer.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observers' Data Access Portal: Realtime Streaming for Astronomical Data","authors":"T. CodaW. M. Keck Observatory, T. OluyideCaltech/IPAC-NExScI, M. S. LynnCaltech/IPAC-NExScI, J. A. MaderW. M. Keck Observatory, G. Bruce BerrimanCaltech/IPAC-NExScI, M. BrodheimW. M. Keck Observatory, C. R. GelinoCaltech/IPAC-NExScI, J. GoodCaltech/IPAC-NExScI","doi":"arxiv-2409.09231","DOIUrl":"https://doi.org/arxiv-2409.09231","url":null,"abstract":"The W. M. Keck Observatory Archive (KOA) has released the Observers Data\u0000Access Portal (ODAP), a web-application that delivers astronomical data from\u0000the W. M. Keck Observatory to the scheduled program's principal investigator\u0000and their collaborators anywhere in the world in near real-time. Data files and\u0000their associated metadata are streamed to a user's desktop machine moments\u0000after they are written to disk and archived in KOA. The ODAP User Interface is\u0000built in React and uses the WebSocket protocol to stream data between KOA and\u0000the user. This document describes the design of the tool, challenges\u0000encountered, shows how ODAP is integrated into the Keck observing model, and\u0000provides an analysis of usage metrics.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Method of Searching for Rotations of the Polarization Position Angle of Quasars","authors":"S. S. Savchenko, D. A. Morozova, S. G. Jorstad, D. A. Blinov, G. A. Borman, A. A. Vasilyev, T. S. Grishina, A. V. Zhovtan, E. N. Kopatskaya, E. G. Larionova, I. S. Troitskiy, Yu. V. Troitskaya, E. V. Shishkina, E. A. Shkodkina","doi":"arxiv-2409.08674","DOIUrl":"https://doi.org/arxiv-2409.08674","url":null,"abstract":"Observations of quasars show that the polarization position angle of the\u0000emission coming from them varies greatly over time, including periods called\u0000rotations during which the angle changes in an orderly manner. The study\u0000proposes a method for identifying such events and assessing their statistical\u0000significance. The operation of the method is demonstrated using the example of\u0000long-term polarimetric observations of the blazars CTA 102, 3C 454.3, and OT\u0000081. During the analysis of light curves, 51 rotations of the polarization\u0000position angle were found and it was shown that for CTA 102 and 3C 454.3 the\u0000rotations are predominantly oriented in one direction.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}